Defect characterisation in amorphous diamond-like carbon coatings

Amorphous diamond-like carbon coatings, produced by ion beam assisted physical vapour deposition IBAD.and plasma enhanced chemical vapour deposition PECVD.on Si 100.substrates have been studied by positron beam and other techniques. Both layers have similar positron annihilation characteristics and a density of 2.4"0.3 g cmy3, and are probably significantly hydrogenated. In the IBAD sample there is significant damage to the substrate, including a deep armorphised region and evidence of defect states at the interface to the carbon. q1999 Elsevier Science B.V. All rights reserved.